Automatically operable touchless washroom devices, such as lavatories and sinks, are becoming increasingly common, particularly in facilities having public washrooms. Touchless washroom devices allow users to avoid touching contaminated surfaces to operate the devices. These devices usually incorporate one or more sensors that detect a person's location and/or movements. A control system then operates a valve or other washroom device component based on the sensor output.
Currently known touchless devices incorporate different kinds of sensors. Active sensors, such as active infrared (IR) sensors, may be used to sense the presence of a person near the washroom device by transmitting a light beam (e.g., an IR beam) and detecting whether the beam is reflected back to the sensor. If a person is near the sensor, the light beam will reflect off of the person's clothing back to the sensor. Different materials and different surface textures, however, reflect light in widely varying different ways. For example, shiny fabrics tend to reflect light more than matte fabrics. Some fabrics even tend to absorb light, making it difficult for an active sensor to detect the presence of a person at all. Moreover, various surfaces, such as shiny tile, tend to reflect light beams back to the sensor, potentially causing the sensor to erroneously detect the presence of a person near the washroom device.
Although systems incorporating two or more sensors are known in the art, these systems either use different sensors to sense a person's presence at different zones and/or distances, to detect a person's presence in different types of light conditions (e.g., high ambient light vs. low ambient light), or to reduce energy consumption by using one sensor to determine whether to activate another sensor. The actual operation of the washroom device, however, still depends on the output of a single sensor in currently known systems, making them susceptible to the inherent operational weakness of the sensor. As a result, the washroom device will not engage accurately, causing either wasted water due to unnecessary device operation and/or user inconvenience due to the failure of the device to operate when needed.
There is a device for a detection system that can detect the presence and absence of a person near the washroom device in a more accurate manner.